This invention relates to control logic circuitry for a color bar code printer.
The record medium produced by the apparatus of this invention may be used in semi-automatic mark-sensing systems for check-out counter applications in super-markets and retail department stores, credit card and inventory control applications, and the like. The record medium may be attached to an item to be sold, for example, and the record medium is read during the sale of the item by an optical probe scanner which is "scribed", or glided, across the record medium.
The record medium produced by the apparatus of this invention utilizes three different indicia, with a first and a second indicia being recorded on one surface of the record medium, which surface is utilized for the third indicium. The finished form of the record medium in one embodiment takes the form of parallel bars of first, second, and third colors. The coded record medium uses transitions of colors to define a binary logic state like a "1" or a "0" rather than use a first color to always define a first binary state and a second color to always define a second binary state, as is done in the prior art. The use of color transitions on the record medium obviates the need for a separate clocking arrangement thereon and considerably reduces the size of the record medium compared to those of the prior art.
Because of the transition code, certain problems were encountered in effecting the design of a logical control scheme for a printer apparatus which would cause a pattern of colors to be printed according to a predetermined code. The chief problem was to design circuitry which would accomplish the above results at relatively low cost. Another problem was to design a control scheme for a printer apparatus which would accurately print the record media according to the predetermined code at a rapid rate while overcoming somewhat severe registration problems. The control logic of the present invention solves these problems.